Human Herpesvirus 8 Induces Polyfunctional B Lymphocytes That Drive Kaposi’s Sarcoma
- Emilee R. Knowltona,
- Giovanna Rappoccioloa,
- Paolo Piazzaa,
- Lauren M. Leponea,
- Sagar V. Nadgira,
- Arlene Bullottab,
- Stella J. Berendama,
- Jun Lib,
- Todd A. Reinharta,
- Frank J. Jenkinsa,b,
- Charles R. Rinaldoa,b
aDepartment of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
bDepartment of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Address correspondence to Charles R. Rinaldo, email@example.com.
Editor Vincent Racaniello, Columbia University College of Physicians & Surgeons
Kaposi’s sarcoma (KS) is an unusual neoplasia wherein the tumor consists primarily of endothelial cells infected with human herpesvirus 8 (HHV-8; Kaposi’s sarcoma-associated herpesvirus) that are not fully transformed but are instead driven to excess proliferation by inflammatory and angiogenic factors. This oncogenic process has been postulated but unproven to depend on a paracrine effect of an abnormal excess of host cytokines and chemokines produced by HHV-8-infected B lymphocytes. Using newly developed measures for intracellular detection of lytic cycle proteins and expression of cytokines and chemokines, we show that HHV-8 targets a range of naive B cell, IgM memory B cell, and plasma cell-like populations for infection and induction of interleukin-6, tumor necrosis factor alpha, macrophage inhibitory protein 1α, macrophage inhibitory protein 1β, and interleukin-8 in vitro and in the blood of HHV-8/HIV-1-coinfected subjects with KS. These B cell lineage subsets that support HHV-8 infection are highly polyfunctional, producing combinations of 2 to 5 of these cytokines and chemokines, with greater numbers in the blood of subjects with KS than in those without KS. Our study provides a new paradigm of B cell polyfunctionality and supports a key role for B cell-derived cytokines and chemokines produced during HHV-8 infection in the development of KS.
IMPORTANCE Kaposi’s sarcoma (KS) is the most common cancer in HIV-1-infected persons and is caused by one of only 7 human cancer viruses, i.e., human herpesvirus 8 (HHV-8). It is unclear how this virus causes neoplastic transformation. Development and outgrowth of endothelial cell lesions characteristic of KS are hypothesized to be dependent on virus replication and multiple immune mediators produced by the KS cells and inflammatory cells, yet the roles of these viral and cell factors have not been defined. The present study advances our understanding of KS in that it supports a central role for HHV-8 infection of B cells inducing multiple cytokines and chemokines that can drive development of the cancer. Notably, HIV-1-infected individuals who developed KS had greater numbers of such HHV-8-infected, polyfunctional B cells across a range of B cell phenotypic lineages than did HHV-8-infected persons without KS. This intriguing production of polyfunctional immune mediators by B cells serves as a new paradigm for B cell function and classification.
Citation Knowlton ER, Rappocciolo G, Piazza P, Lepone LM, Nadgir SV, Bullotta A, Berendam SJ, Li J, Reinhart TA, Jenkins FJ, Rinaldo CR. 2014. Human herpesvirus 8 induces polyfunctional B lymphocytes that drive Kaposi’s sarcoma. mBio 5(5):e01277-14. doi:10.1128/mBio.01277-14.
- Received 30 April 2014
- Accepted 25 July 2014
- Published 2 September 2014
- Copyright © 2014 Knowlton et al.
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